PDCD4 and melanoma: Using a large historical cohort of 523 melanoma cases (230 primaries and 293 metastases largely from extracranial sites) and a cohort of 263 benign lesions, we found that PDCD4 expression was significantly higher in benign vs. malignant tissue regardless of subcellular localization (ANOVA, p < 0.0001), Figure 1a.